a. Field of Invention
This Invention relates to novel processes for the production of indole derivatives.
More specifically, this invention relates to the process of the production of tricyclic acetic acid derivatives in which the tricyclic portion thereof is characterized by having an indole portion fused to a pyrano ring. Still more specifically, the process of this invention produces the following tricyclic acetic acid system: ##STR1## designated 1,3,4,9-tetrahydropyrano[3,4-b]indole-1-acetic acid in which the carbons at the 1- and 4-position, and optionally at the 5-, 6-, and 8-positions are further substituted.
The indole derivatives produced by the present process are described in Katz et al U.S. Pat. No. 4,670,462 and Katz et al U.S. Pat. No. 4,775,690, and herein incorporated by reference.
The indole derivatives produced by the present process are known to exhibit useful pharmacodynamic properties without eliciting undesirable side effects. Notable attributes of these derivatives are anti-inflammatory and analgesic activities.
b. Prior Art
The closest prior art to the present invention is:
Katz et al, U.S. Pat. No. 4,670,462; Katz et al, U.S. Pat. No. 4,775,690; and Demerson et al, U.S. Pat. No. 3,939,178. Demerson et al disclosed the production of 1,3,4,9-tetrahydropyrano[3,4-b]indoles and 1,3,4,9-tetrahydrothiopyrano[3,4-b]indoles having analgesic and anti-inflammatory activity. Related U.S. Pats. are Nos. 3,974,179 and 3,843,681.